.673″ high x .499″ wide x .078 deep. “STERLING PAT. 1861263” is stamped on the inside of the back cover. Sterling silver body. Sterling silver shackle. A trick padlock. Press the button on the reverse of the case to open the lock. “Century Of Progress International Exposition” was the title of the 1933-34 Chicago Worlds Fair.Patent # 1861263.